Insulating confined spaces



April 13, 1948. c. c. HERITAGE INSULATING CONFINED SPACES 2 Sheets-Sheet 1 Filed March 2, 1945 Wm w w 2 7??672207 UZarZ' (23277765 6 c. c.v HERITAGE I 2,439,603

April 13, 1948. I

IiIsULATING CONFINED SPACES Filed March 2, 1943 2 Sheets-Sheet 2 Patented Apr. 13, 1948 INSULATING CONFINED SPACES Clark 0. Heritage, Cloquet, Minn., assignor to Wood Conversion Company, Cloquet, Minn., a

corporation of Delaware Application March 2, 1943, SerialNo. 477,754

3 Claims. 1

The present invention relates to the placement of particles of thermal insulating material to build up a thermally insulating integrated mass of such material in a confined space. In particular it relates to carrying the material in a gaseous vehicle (hereinafter referred to as air) to a deposited growing mass of such particles formed by deposition of particles from the vehicle.

In its general aspect, the invention contemplates completely confining a space to be so filled with insulation material, whereby to define the form of the mass to be produced. The space may be provided substantially completely by or within existing articles. However, as required or desired for the purposes of the invention, the space to be filled is completely defined by bounding facial walls having essentially some filtering area for exhausting the gas in which particles of the insulating material are introduced, and having essentially in the area of the confining walls one ormore inlet areas for introducing the gas containing the particles, each such inlet area being essentially in and a fraction of a confining wall or face in a manner analogous to the relation of the area of a pouring sprue in molds for casting metal articles to a spacedefining area of the mold.

It is also a. general aspect of the invention that the particles of insulating material are such as may be consolidated into a gas-filtering body,

. when in finally deposited form, whereby in conducting and completing the introduction, gas entering the space through inlet area may pass through all or a part of the body as required to exhaust through filtering area.

Another general aspect of the invention permits the form of the space to be complex, or

angular, and not limited to panel-form spaces. Thus, the vehicular stream of gas is introduced at a differential pressure, relative to the pressures at inlet area and at. filtering area, and at such a velocity that the particles suspended in the gas are carried with turbulence inside the 2 cabinets of refrigerators, such as are used in homes.

In the field of artificial refrigeration, high standards for insulation in domestic and other refrigerators have developed in order to minimize heat loss, because high heat loss adds to the cost of operation. Considerable difficulty has been encountered in the commercial development of refrigerator insulation in parallel with the development of domestic artificial refrigeration. Along with high standards and for low heat loss, low cost of insulating material and of insulating process are important, as are uniformity in each cabinet, and uniformity from cabinet to cabinet in a production line.

In addition, there is the problem of permanence, in which resistance to settling of packed bulk insulation is most important. Such resistance can be attained by increasing the density of packing, with which heat leak or heat conduct ance increases, as a general rule, in the ranges encountered in refrigerators. It is, therefore, important to minimize density, consistently with acceptable resistance to settling and acceptable insulating value. All these factors lead to a need for a process which is subject to control for meeting them.

In the prior art there has been no low-cost process for packing a specified material uniformly and integrally into a cabinet, and uniformly from cabinet to cabinet in a production line. The present invention provides such a process, and so used it gives reproducible results with any reproducible material. Vegetable fibers such as from wood may readily be produced from time to time with reproducible properties within given specifications, and with such material and with the present invention, a low-cost process for uniformly'and efficiently insulating spaces, such as those in refrigerators, becomes available to the manufacturers of refrigerators. Reference is made to my copending application Serial No. 336,495, filed May 22, 1940, now Patent No. 2,325,055, issued July 7, 1943, describing reproducible fibers, which are useful as particles for practice of the present invention.

It is an object of the present invention to insulate a refrigerator cabinet having a door opening, in which cabinet there is mounted a food compartment, where there are openings in each of the cabinet and the food compartment to accommodate the insertion into the food compartment of a refrigerating unit.

It is a particular object of the invention to introduce insulation into the space between said food compartment, by introducing a stream of gas containing insulating particles, into such an opening for the unit, and preferably through such an opening in the cabinet, while filtering gas from said space through filtering area in part in the other opening and in part at the door opening of the cabinet.

Various; other; and ancillary objects and advantages of thei'nvention will appear. from. the.

following description and explanation of the invention set forth below with reference to the. accompanying drawings in which:

Fig. 1 represents in perspective a refrigerator cabinet in horizontal position with its-door.-opening facing downwardly and with its food compartment mounted therein, there being an opening in the back face of the cabinet connected withmeans.

cabinet back, and showing areversalin position of the inlet areafor insulating materialand the opposite filtering area; and f Fig. 5 illustrates a blower and feeding means therefor which is connected to the hood shown in Figs. 1 and 4.

In my earlier application Serial No. 294,212,- the process is described generically and-specifically with respect to variousforms of the space to be filled, and various types of space-confining walls, and removable fixtures, having particular reference to variations in the process for insulating domestic type refrigerators. These variations include filling a refrigerator in which the food compartment is ah'eady mounted, and also in which the food compartment is not. mounted. In,;the latter case, a fixture in the formof-a dummy for the food compartment is employed, andthe'fixture is used to provide filtering area, and may be used to provide inlet area. The processisfiexible foraccommodating it to various types of; refrigerators, as well as various types of spaces not necessarily those of; refrigerators.v In the said. earlier application there isclaimed specifically a method of filling a refrigeratorin which the food compartment is mounted, both the cabinet and. the food compartment having openings therein.

for accommodating. the insertion: into thefood compartment of a refrigerating unit; Oneof the said openings to the space is used. for introducing the gas, while the other. is blocked off. Theiopen.

space at the-door opening between the cabinet. and the food compartment, where breaker-strip material is located. in the completed refrigerator, is closed by. a. fixture. or closure provided with filtering; area, and preferably including also some imperforate area. Thus, the gas introduced passes through the gas-filtering body of insulating mate rial built up in the-space. Thenthe fixture isre moved; and breaker strip used toclose the: gap.

Thespacebetweenthe openings for the unit thus has insulation,.which. may be disturbed as'neces sary i making connections when installing the refrigerating unit.

Itis also setforth that the streamis introduced at a differential pressure betweeminlet andi filter areas; This ma be eifectediby. having atmospheric pressure at :eitherthe; i'nletarea, or at. thefiltering area. The latter is preferred for many practical and mechanical reasons.

In the present application it is likewise intended that the pressure be a differential one, but to simplify the description and the illustration, only the preferred one of super-atmospheric pressure at inlet area, is specifically described and illustrated' Without intention to limit the. invention thereto.

After the introduction of the insulating material into the space to be insulated, especially in a refrigerator, there are numerous mechanical operations which may be necessary to complete the article; for use or sale; However, these form no essentialtpart of the invention, and detailed description and. illustration of them are herein omitted- The preferred closures or other means having filtering area are preferably permanent fixtures used in a production line, and are in preferred practice removed after each use- However, these may be of other structure, for example, metalor cloth filters of such character that they need. not. be removed. When retainedrthey. maybe av permanent part. of the final structure, covered. or not. Hence, theremoval 0f suchclosuresisnot considered an essential part of .the process. But in certain cases, it may be includedasan essential part of certain aspects or variations of' the invention,

The present invention may be. usedfor fibers, fiakesand particles of other. forms. Examples-of fibers are hair, wood fiber, vegetable fiber, kapok, mineral wool, glasswool, asbestos, straw, grasses and many others. Examples of other materials are flaked paper, exfoliated vermiculite, mica, ground cork and like material. Fibers are preferred, becausethey mat and felt and produce stable forms in more complex variations of the,

invention wherefix-tures may be used and.- removed. The following illustrations are therefore given with respect to wood fiber, such as that according to my said copending application Serial No. 336,495, filed May 22, 1940, now-Patent.- No. 2,325,055, issued July 7', 1943, which-was; developed primarily for use in the present. in.

vention. 1

The invention involves; the, building upof' a consolidated gasefiltering body of particles? of insulating material introduced as suspended :mate ter'in a stream of. gas, into a confined-space-to bev insulated; and it involves the provision in the confining wallsof' said: spaceof: filtering area'gtou retain the particles andiexhaust the gas=.. 'Ilhe; location of-inlet area, the number of inletareas; and the location, size and numberofi filtering:

areas are: not. critical 1 with. respect-to any given space.

space: The. greater. the shortest. distance. from inlet area: to filtering area, the thicker isthe body. of: insulating material through. which gas must pass to exhaust. Therefore, for practical convenience, itiisldesirableto' have filtering area close to, or even adjacent toinlet area.- Experience: hasshown. that, becauseof the turbulence;

the: particles. may deposit"; in regions some ofwhich are adjacent. to filtering: area, and others-v of which are. remote from both inlet: area. and

adjacent inletareafacilitates thexdepositionof The conditions;

the: last-deposited material;

This .iszbecause the stream offgas isintror-f duced at a velocity to impelithe particles: with, turbulence. into. the space. and to all parts. of thes establish a complexity of air currents which change as the remaining space to be filled changes. Cyclonic currents have been observed which tend to throw carried particles centrifugally out of the local air stream and deposit them by centrifugal force and in the manner described. Also direct deposition by filtration has been observed as one of the resulting actions to deposit the introduced particles.

In my earlier parent application Serial No. 294,212, the drawings illustrated a refrigerator cabinet having within it its food compartment, being filled .by an inlet hood over the opening in the cabinet for the refrigerating unit, while a baflle-plate closure is mounted in the opposite opening for the unit in the food compartment.

the filtering area being provided in a four-sided frame which fits as a fixture over the peripheral intervening space at the door opening of the cabinet. However, it is stated therein that the said baffle may be replaced by means providing filtering area, and also that the same hood and the said means may be reversed so that the hood is over the unit-opening in the food compartment. The present application is directed to these modifications.

In Fig. 1, a cabinet ID with its door-opening downward, has mounted within it a food compartment ll, shown in part by full lines of a fragment only, and otherwise by the dotted lines designated II. An opening l3 in the back of the cabinet for accommodating a refrigerating unit to be inserted in the food compartment II is covered by a hood l4, connected to a conduit I5, and having window It. The food compartment ll having an opening I8 opposite opening [3. likewise to accommodate said refrigerating unit, is closed by a plate l9, having in it a screen 20, to provide filtering area.

The door opening has an exposed peripheral area communicating with the space to be insulated, and this area is closed by a substantially rectangular frame shown in Figs. 2 and 3, proare illustrated in dotted lines with flanges turned 1 toward the intervening space. The cornersbetween the frames have imperforate area provided by connecting material 25. Betweenthese corners, and between the members of the two frames, are wire screens providing filtering areas 26.

Fig. 4 shows the same cabinet [0 with its food compartment H on its back. The same frame is used on the door-face of the cabinet in the same way. The opening in the cabinet is here designated 30, and it is covered by a plate 3| (like plate l9), having a screen 32 therein to provide filtering area. The opening in the food compartment H ,is here designated 33, and it is closed by hood 34, connected to conduit 35.

Fig. 5 shows a blower system to which the conduits l5 and 35 may be connected. A fan-type blower 45 has pipe 46 for the entry of air, into which fiber may be fed by hand, or by a mechanical device, such as a picker, or a worm screw 46a. The fan discharges downwardly through conduit 41.

Consider the apparatus of Fig.5 when the pipe 41 is 6 inches in diameter and connected to a fixture for filling a space. The fan is operated at 3740 R. P. M. by a 15 H. P. motor of 1800 R. P. M.

6; Running idle (connected and operated but no fiber fed), the measured pressures are as follows:

Table I Pressure in inches In plpe 47 of water Lateral (static) pressure 8.5.

10.25. 1.75. 5300 ft. per minute. 1040 cu. ft. per minute.

The system shown in Fig. 5 has been used to fill a certain space A full, then to /2 full, then to /1 full, and then to full, with measurements of the system (idle) at each stage. The measured values are combined in Table II with values taken from Table I and are in the same units as those in Table I.

It is noted that under conditions where the exit is wholly or to a degree blocked, as when the space is full, there is a back pressure encountered at the inlet to the centrifugal fan.

The back-pressure is an important feature of the use of super-atmospheric pressure feed, with apparatus permitting back pressure. Consider in Fig. 5 that the fan may run while the feed line 41 is open. A momentum is established into pipe 41. As this is blocked off, the moving stream is retarded, at first in part, and fiber gradually fills up the inlet conduits. A window (earlier described) indicates this and the process may be stopped. If not stopped the back pressure at the inlet blows fiber back in pipe 45. Thus, fiber fed into the inlet will also be blown out the inlet. The appearance of bacl -feed or back-pressure is an indication of the final status of being filled.

Many factors influence the result, and practically, it is necessary to arrive at standard conditiorrs for the particular equipment used, and the job at hand. For example, it has been found to be a general rule, that the faster the fiber is fed, the less the density of the mat obtained. However, this rule is limited to a very short period of time. In one tested instance the feeding time for the space was varied from fractions of a minute to several minutes. The curve of density has been plotted vertically against feeding time plotted horizontally, The curve rises rapidly, and at about 25 seconds it begins to flatten out.- In about 60 seconds it has reached a maximum density. Such curves were obtained with different fan speeds, and it was found that high speeds (greater kinetic energy to fiber) at the same feeding time gave higher density mats. By constructing such curves from experimental procedure, the conditions for most efiicient operation and for uniform operation may be easily determined.

By using the described filtering area opposite the inlet, there may be formed in operation a filtered mass of fibers which acts as a bafile to defiect the air stream laterally in all directions from the inlet area.

The use of a fan is preferred for the reason that it is a means of unfeltingthe fibers to subagesaoos stantially individual fibers; It i's this form which However,- broa'dly, the:

ivesthe" best results.- fibers need not be completely unfelted, and may bein clustersor small aggregates, Uses of other means, such as. vacuum on the screen end, or feeding, fiber directly into a current of air, is conducive to providing suchloose aggregates, rather than individual, particles of fiber; The important pointv is: that theseare not under; me chanical pressure; to, felt them, and they tend: to unf'elt in process;

The terms screening means and filtering area-i" as used herein or in the claimsrefer to an area-Withany effective lattice or perforated membar" which: acts asa screen to filterparticles from the carrying gas, and it: is to be distinguished from armember porous to air and from a-crack or" an: elongatedslot;

It is not essential that fiiter-ing areabe limitedall such that particles are introduced withturbur.

lence in. all. portionsof the space to be filled, and pack.therein.

Numerous modifications and. variations of the invention, not necessarily confined torefrigera tors, are contemplated as fallingwithin the scope of the appended claims.

Irclaim 1. In depositing particles to form insulation in situ in a: refrigerator formed of inner and outer shellseach' withan openface together providing anxopeningfor closure by a door, which shells provide a continuous space-between them opening through screening: means in said dooropening, each of said shells having anopening'in its well opposite'said door opening to permit installation of acoolingunit,. of which two well openings one provides an introductory inlet to said space:

of sizerelatively large compared withthe foramina of. said screening means, and the other: is covered by a closure including, like: screening, means, the method which oomprisessuspending in .a"- moving gas; particles of insulating material which pack. to a consolidated body that is a gasfiltering body at an insulating. density-of the; sopacked particles; introducing the :resulting moving gaseous suspension into said: space by con ducting; the suspension; toand through saidrintroductory inlet; simultaneouslyventingsaid;

from-said space: through said screening: and there filtering: saidvented' gas from; par-tic thereby depositingand packing particlesito foimr aigrowingi gas-filtering mass thereof? in com-es spondingiportions of: said: spaceover and exte ing away from said screening means; simulta neously' maintaining; in the: remaining portion of saidzspace a conditionofturhulence ofi'said eous. particlersuspension; by maintaining high at an insulating density and resultingly molded into-said spaceand compressed therein by-the differential introduction pressure between said inlet and said screeningmeans;

2; 1n depositing par-ti'cIes-toform insulation insitu in" a refrigerator form'ed of'flinner and outer shells each: with an open "face together providing anopeni'ng for closure by a door, which" sh'ell's provide a continuous space'between them'open ing through screening means in said door openmg; each ofi'said shells-having an openingin'its wall opposite said door opening to permit installation: of a cooling unit, of which two wall openings that in the'outer shell provid'esan iirtroductory inlet tosaid'space of size relatively large compared withthe foramina of said screening-means; and the-other is covered-by aclosure including like screening means, themethod which comprises, suspending in a" moving'gas, particles of 1 insulating-- material which pack to a consolidated body that is agas-filteringb'ody at an insulating density" of the so-packedparticles; introducing the resulting moving gaseous" suspension into said space by conducting'thesus- 1. pension to and through said introductory" inlet; simultaneously venting said gas fromsaidtspac'e" through said screening means, and there filtering, said vented gas from-particles; thereby depositing and-;packing-particles; to' form a; growing gasfiltering mass thereof in-, corresponding, portions. of said space over and extending away from said screening means simultaneously maintaining; in the remaining portion of said space a condition of turbulence of said gaseous particle suspension therefor inintroducing said suspension whereby. the turbulence causes; deposition" and packing, of particlesin margins of'the t'urbulentspace; and continuing said introduction, said maintenance ofturbulence, and said venting of said gas, through said'screening means and also through; saidgrowing mass at least until a body of said' particles begins to form in saidinletl and. said. spacefis-completelypackedwithsaid particlesconsolid'ated to a gas-filtering bodyat ariiinsul'atingr density, andfresultingly molded into said space. and'icompressed vthereinlby thedifferential intro; duction" pressure between said" inlet: and. said.

screening means.

and"sufficient:velocitytherefbrin introducing venting of; said gas through said screening meansandia lsozthrough saidgrowingmass at least untit a body of said particles begins to form iir inlet; andv t saidspace: is completely packed was saidr'partioles' consolidated to a gas filtering'bod'y' 3: In" depositing particles tov form. insulation in; situ in' a refrigerator formed of inner andout'er, shells eachwith an open face together providing, an opening for closure by a. door,- which shells: V providea continuous space between them opening outwardly through screening, means. including screening means in said, door. opening. eacirofr said'shells having an opening, in itswallopposite. said door opening. to permit installation of; a, cooling unit, of whichtwowall openings one pro vides an introductory inlet to said: space of size. relatively large, compared with the forami'nahof saidscreeningj means; and the other is covered by a closure. including like screening means, the method which. comprises, suspending, in a moving gas, particles" of insulatingmaterial which pack to aconsolidatedbody that is'a gas-filteringbody. at an insulating density of the so-packed particles; introducing" the" resulting moving gaseous suspensioninto saidspace' by conducting the sus.-' pension"to and through said'introductory inlet; simultaneously venting said gas from said space through said screening means, and thereiiltering saidvented gas from -particles, thereby depositing' and"-packing particles to forma l-growing; gas"- filtering mass thereof in corresponding portions by maintaining, a high and sufl'icient velocity 9 of said space over and extending away from said screening means; simultaneously maintaining in the remaining portion oi said space a condition of turbulence of said gaseous particle-suspension by maintaining a high and suflicient velocity therefor in introducing said suspension whereby the turbulence causes deposition and packing of particles in margins 01 the turbulent space; and continuing said introduction, said maintenance of turbulence, and said venting of said gas through said screening means and also through said growing mass at least until a body of said particles begins to form in said inlet and said space is completely packed with said particles consolidated to a gas-filtering body at an insulating density and resultingly molded into said space and compressed therein by the difierential introduction pressure between said inlet and said screening means.

CLARK c. HERITAGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,439,603. April 13; 1948. CLARK O. HERITAGE It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Column 2, line 46, after the word and period invention. insert the following paragraph:

The present invention is a continnation-in-part of my prior application Serial No. 294,212, filed September .9, 1939, wherein the princi les of the process are disclosed, which application is generic to the present app ication. and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the casein the Patent Oflice.

Signed and sealed this 11th day of May, A. D. 1948.

[sun] THOMAS E MURPHY, V

ui tmt T omm adel er of Patents. 

